To many of today's enterprises, continuity of business operations is vital. Strategies for protecting business-critical data against local or widespread disaster abound. Such strategies include backup and recovery strategies and disaster recovery strategies. Backup and recovery strategies generally involve frequent, regularly scheduled procedures for backing up critical data. Typically, copies of backups are maintained locally to facilitate rapid restoration of lost or corrupted files or data. In contrast, disaster recovery strategies address situations of complete loss or inaccessibility to the entire data center of the enterprise, including all data files, application programs, and stored backups. Disaster recovery generally entails replicating the information stored at the data center and transmitting it to a data center at a remote location.
To implement backup and recovery strategies and disaster recovery strategies, many software products are commercially available. An example of a software product for non-disruptively generating local copies of data for backups is TimeFinder®, produced by EMC Corporation of Hopkinton, Mass. Remote replication capabilities may be accomplished through software products such as Symmetrix Remote Data Facility® (SRDF) and MirrorView®, also produced by EMC Corporation.
For business-critical data, an enterprise's information technology (IT) department typically arranges to have local backups performed frequently and remote replication performed continuously (i.e., synchronously, in real-time). Replication of other, less critical categories of data typically occur on a scheduled basis (i.e., asynchronously), often after business hours, to capitalize on lower pricing for bandwidth use. Business operations can continue to use the data in the storage system throughout the replication process. The unpredictable nature of natural and manmade disasters, however, can jeopardize an enterprise by striking at a moment when all data has yet to be replicated and moved to a remote location.
Industry has recognized this vulnerability and devised a solution for servers and personal computers. The solution entails environmental sensors, disposed locally to these machines, which signal an impending local disaster. Each server and personal computer capable of interpreting such warning signals pushes its data, as an incremental or full backup, to a corresponding server or computer situated at a safe distance from the disaster.
Problems inherent with this solution, however, present themselves when the disaster extends farther than the servers and computers are able to move their data in accordance with their data evacuation floor plans. Moreover, local area networks to which the machines are interconnected may not be able to support the flood of data from the many servers and computers individually contending for the limited bandwidth in their urgent attempt to preserve their data. The situation becomes dire for any server or computer that is offline when the disaster occurs, there being no opportunity to save its data. Further, the added cost of equipping servers and computers with the capability of interfacing and interpreting signals from environmental sensors would limit the use of this mechanism to those machines having data deemed worthy of the added expense.